1. Field of the Invention
The present invention relates to an equalizer-based receiver in a mobile communication system. More particularly, the present invention relates to an apparatus and method for reducing power consumption of the receiver by decreasing a multi-tap size in an equalizer-based receiver in a mobile communication system.
2. Description of the Related Art
With recent standardization and commercialization of a mobile communication system that requires high-rate data transmission, such as a Wideband Code Division Multiple Access (WCDMA), High Speed Downlink Packet Access (HSDPA), and the like, research is presently conducted for an equalizer-based receiver suitable for high-rate data reception.
A conventional equalizer-based receiver includes an equalizer and a multi-tap channel estimator having a tap long enough to sufficiently receive a delay profile of a reception channel. The multi-tap with a sufficiently long length is designed where a multi-path reception channel has a long delay profile. However, in an actual channel reception environment, the multi-path reception channel does not always have the long delay profile.
Therefore, in a conventional method, the multi-tap with a long length is selectively used according to a channel environment without having to use all multi-taps. That is, a receiver estimates a delay profile of a received signal according to a multi-path to lock only a necessary tap among the multi-taps, and receives a signal by unlocking the remaining taps. The method of using the necessary tap by locking only the necessary tap can reduce power consumption since hardware elements are less used in certain situations and can remove performance deterioration caused by noise when a tap not having multi-path energy is locked.
Although the multi-tap with a long length is designed where the multi-path reception channel has a long delay profile, there is a decreased probability that the multi-path reception channel actually has such a long delay profile.
Accordingly, a channel estimator for guaranteeing performance of a receiver will have a long tap and hardware elements of the channel estimator will operate with a sufficiently long tap.
Therefore, a need exists for an equalizer-based receiver in a mobile communication system with a decreased multi-tap size for reducing hardware size and power consumption.